Drilling machine,in particular for offshore drilling



, ilnit ed States Patent lnventor Jean-Michel Marie Tissier.

18, Ave de Verdun, Chatillon-sous- Bagneux, Hauts-de-S eine, F rahce Appl. No. 774,012 Filed Nov. 7, 1968 ent d. 0. 51.1979. Priority Nov. 7, 1967,

France,

DRlLLlNG MACHINE, IN PARTICULAR F OR OFFSHORE DRILLING 5 Claims,.1l Drawing Figs.

U.S. Cl 173/37, 74/841. 173/160,173/l64, 175/6 lnt.C1 E2lb 7/12 Field of Search 175/6;

References Cited I UNITED STATES PATENTS 642.552 1/1900 Landin 173/37X 2,849,212 8/1958 Robbins 173/37X 3,442,339 175/6 5/1969 Williamson Primary Examiner- Ernest R. Purser l t z orneys K enyon and Kenyon, Reilly. Carr and Qhapin ABSTRACT: The drilling machine, in particular for offshore or underwater drillings, comprisesa crane consisting of a bracket secured to a base resting on the ground through the 7 medium of legs, a turn table capable of rotating a string of drill pipes, a pushing device for instance of the screw pushing type, capable of driving bits and strings of pipes into the ground, a screwing and unscrewing device for the strings of pipes and a device for pulling out strings of pipes and drilling cores, The machine is powered'by pressurized hydraulic fluid actuated motors and cylinders individually driving the members of the machine, and notably the turn table the pushing screw, the baselegs and members for tightening or holding the string of drill pipes.

DRILLING MACHINE, PARTICULAR FOR OFFSHORE DRILLING The present invention relates essentially to a drilling machine, in particularv for offshore or under water drilling, of the type comprising a frame consisting of a bracket secured to a base resting on the ground (in particular on a sea bed) by means of legs, a device called turntable capable of rotating a string of drill pipes, a pushing device, for instance a screw type pushing device, capable of driving drilling bits and strings of drill pipes into the ground, a device for screwing and unscrewing strings of drill pipes, as well as a device for pulling out drilling pipes and cores in particular.

More specifically, the machine according to the invention is an improved version of a machine described in the French Pat. No. l,499,2l5 entitled: Method of offshore drilling and equipment for putting the said method into practice.

As mentioned in the aforesaid patent, the prior art machine generally used to carry out underwater drillings was of a type widely used for land drillings and was mounted aboard a barge brought to a standstill by means of anchors over the sea bed to be drilled. As described in the said patent, considerable difficulties had to be overcome when using this technique In fact, the results obtained byv these known techniques are quite unsatisfactory and even deplorable when the sea bed lies at a certain depth in the region of some 30 or 50 metres maximum.

Contrary to the conventional offshore drilling techniques, the said patent disclosed an entirely novel technique according to which the drilling was performed by means of an immersed machine suitably anchored to the sea bed to be drilled.

Underwater control of this machine was simply performed by divers and the machine was powered from a ship stopped above the drilling location and connected to the machine by means of flexible feed cables.

The machine described in the said patent was of a rather conventional type and simply adapted for underwater use and powered by means of compressed air.

The present invention relates to an improved machine of novel design, remarkable by its adaptability and convenience in underwater use and allowing to reduce to a minimum the operations to be carried out by the divers. Practically, the latter are only required to supervise the machine operated at a particularly high working rate.

Thus, according to one feature of the invention, the machine is powered by means of a pressurized hydraulic fluid which actuates the hydraulic motors and cylinders controlling the various members of the machine such as a turntable, a

pushing screw, base legs, tightening members for the string of drill pipes. The pressurized hydraulic fluid is provided by a hydraulic power plant composed, for instance, of a diesel engine driving a variable displacement and pressure pump, the said plant being mounted aboard the said ship anchored above the machine. This diesel engine advantageously drivesa slush pump ensuring the lubrication of the string of drill pipes during the course of drilling and a low voltage generator for feeding auxiliary controls and the underwater illuminating system. The machine and the power plant are interconnected by means of flexible cables and pipes. The latter are designed so as to be capable of being rapidly provided with extensions (rapid couplings), and check valves are provided in the various circuits to prevent hydraulic fluid losses and water inflows in case of pipe breakage.

According to another feature of the invention, the hydraulic motors used with the drilling machine advantageously consist of variable speed motors with rotating speeds ranging, for instance, from a few fractions of a revolution per minute to several hundreds or thousands of revolutions per minute.

Owing to the possibility of separately varying the operation of the various hydraulic motors with respect to speed and turning moment, and. also owing to smooth operation of the hydraulic drive of the various motors, it will be understood that this new machine can carry out any kind of drilling in any type of ground in the best possible conditions. In particular,

shearing of the drill pipes, jamming or racing of the motors are avoided. Jamming of the string of drill pipes is also avoided.

According to a further feature of the invention, all the rotating members and control members of the machine lie in pressurized hydraulic fluid, and this prevents water, in particular corrosive sea water, from unduly entering the machine, whereby the life of the various members of the machine is considerably extended.

According to still another feature of the invention, separate motors are provided, in particular, for the-tumtable and for the motion of translation of the pushing screw. As a result, the motions of rotation and translation of the drilling bit can be controlled separately during the drilling or coring operation, thus allowing to select at every moment the most appropriate rotating and driving-in speeds, depending on the nature of the soil. In particular, jamming of the bit and premature breakage of the drilling crowns are avoided.

According to still another feature of the invention, each supporting leg of the machine (preferably provided with three legs) may be raised or lowered by means of a separate hydraulic motor provided with a separate control. Thus, when the machine is set on the sea bed to be drilled, it can easily be placed exactly horizontally by raising or lowering each leg of the tripod. Once the machine is conveniently placed, the legs may advantageously be anchored by any appropriate means such as mine bars, etc.

According to still another feature of the invention, the bracket maybe tilted with respect to the base so as to form a certain angle with the vertical; this motion is controlled, for instance, by a hydraulic cylinder, said bracket being hinged on the base through the medium of a substantially horizontal axis. This, in particular, enables to rapidly pull out the cable core barrel by means of a top winch which is thus automatically centered on the vertical above the drill hole. This automatic centering of the winch is ensured by the preset tilting travel of the bracket. Thus, the pulling out of the cores is accomplished extremely rapidly.

According to still another feature of the invention, the pushing screw for the drill pipes is pivotably mounted by means of ball-and-socket devices at either ends thereof, thus enabling to take up plays and ensuring the operation of the screw in the best possible conditions. V i

According to still another feature of the invention, the tightening device for the string of drill pipes comprises a hydraulic vice or holder. Divers work is thus reduced to a minimum, more especially as a guiding vice, for instance a hand-operated guiding vice, is advantageously provided above the tightening vice. According to an improved modification the feeding of the drill pipes may be performed entirely automatically.

According to still another feature of the invention, the frame of the machine, consists, at least partially, of impervious box girders filled with a fluid, for instance a hydraulic fluid, the latter being advantageously maintained at a pressure substantially equal to the hydrostatic pressure of the surrounding medium. This enables to reduce the transportation weight to a minimum while ensuring maximum strength and keeping on sea beds.

According to still another feature of the invention, the screwing sleeve for the string of drill pipes is mounted so as to be slidingly translated along a given path on the driving head of the string of drill pipes, the said sleeve rotating integrally therewith. For instance, the screwing handle forms a cylinder and the end of the driving head forms a piston, the whole thus fonning a damping device when strips of drill pipes are being screwed or unscrewed. Such an arrangement enables to avoid untimely deterioration of the threads of the strip of drill pipes, especially when itis being unscrewed.

- The invention will be better understood and further characteristics and advantages thereof will appear as the following explanatory description proceeds with reference to the accompanying drawings given by way of example only, illustrating one embodiment of the invention and wherein:

FIG. 1 is a somewhat diagrammatic perspective view of the main members of the drilling machine according to the invention;v

FIG. 2 is an elevational view and FIG. 3 is a side view of the machine, illustrating the hinged connection between the bracket and the tripod, aswell as the operation of the legs;

FIG. 4 is a diagrammatic view illustrating more specifically the rotating and pushing assembly for the drive driving heads of the string of drill pipes;

FIG. 5 shows, at a larger scale, the turntable and the pushing assembly for the driving heads of the string of drill pipes;

FIGS. 6 and 7 are sectional views, at a larger scale, respectively along the line VI-VI and VII-VII of FIG. 5;

FIG. 8 is a sectional view of the tightening holder or vice for the string of drill pipes;

FIG. 9 is a side view of the same vice;

FIGS. 10 and 11 are diagrammatic views illustrating the operation of the damping device comprising a piston for pulling out the string of drill pipes.

Referring to FIG. 1, a drilling machine according to the invention comprises mainly: a frame composed of a bracket secured to a base 21 forming a tripod resting on the ground through the medium of legs 22; a turntable 23 and a pushing assembly 24 comprising a pushing screw 25 and a tightening device forming a vice 26 for the string of drill pipes (not shown). As already mentioned, the machine frame advantageously consists of impervious box girders filled with a pressurized hydraulic fluid. Any appropriate known type of device (not shown), such as a nitrogen container, hydraulic accumulators, a surface or automatic water-pressure actuated hydraulic control device may be provided to maintain within the box girders a pressure substantially equivalent to the hydrostatic pressure of the surrounding medium. This prevents the box girders from collapsing and enables to give the machine considerable weight favoring the drilling operations. In case of transportation, the box girders may be emptied in order to reduce the weight of the machine. In a modified embodiment, the box girders may also form ballast means.

As shown in FIG. 1, each leg 22 comprises a base 27 by which it rests on the sea bed. The bases 27 are advantageously mounted by means of a toggle or knuckle integral with threaded stems 28 which are prevented from rotating with respect to the base 21, for instance by means of longitudinal slots 29, provided on the screws 28 and cooperating with a projection (not shown) integral with the base 21. Adjacent to each leg 22 is provided a hydraulic motor 30 which drives a gear (not shown) mounted in a housing 31 and engaging a nut (not shown) screwed on the screw 28 and thus controlling the motions of translation (upwards and downwards) of the legs 22. Each leg 22 can thus be separately raised or lowered by simply actuating the motors 30 and, therefore, it is possible, by acting on the hydraulic drive of each motor 30, to position the base 21 correctly, that is to say horizontally, on a sea bed of any relief.

The skids 27 are advantageously removable or interchangeable and are mounted on the machine according to the nature of the sea bed to be drilled.

In order to ensure correct operation of the machine, there may be provided, for instance, a pendulum to determine the correct vertical line of the location which must be placed opposite a reference mark, and also three control knobs for each motor 30 to enable correct raising or lowering of the legs. Once the machine is correctly positioned, the diver controlling the machine actuates a safety device to lock the motors 30 and to enable actuation of the drilling controls which otherwise are locked. This prevents troubles such as tilting of the machine during the course of drilling, eventually resulting from incorrect positioning of the machine. It should be noted that once the machine is correctly positioned, a complementary anchoring of the legs is usually effected, for instance by means of mine bars passed through appropriate openings in the skids 27. 8

Referring again to FIG. 1, it can be seen that a hydraulic motor 32 is mounted on a turntable 23 to rotate the driving head 33 of the string of drill pipes, as described more in detail hereafter, in particular with reference to FIG. 5. The turntable is mounted on a carriage 34 which is guided vertically along rails 35 fixed in any appropriatemanner to the bracket 20.

The guide rolls of the carriage 34 appeanmost clearly in FIGS. 1 and 2. 1

The pushing assembly controlling the pushing screw 25 and which will be described rnorein detail in connection with FIG. 5, comprises mainly a motor 36 (FIGS. 2 and 5) driving a gear 37 engaging a-nut 38 screwed o rrthe pushing screw 25 and prevented from rotating. Inorderto prevent the screw 25 from rotating while, atthe same, time, allowing it to be translated, there is provided, for instance'two diametrically opposed locking slots 39 cooperating with two projections (not shown) integral with the bracket20.

At 40, in FIG. 1, is shown a hydraulic motor for driving a winch 41 whose function will appear more.clearly in connection with the description of FIGS. 2 and 3.

Further, a hand-operated guiding vice is shown at 42 in FIG. 1 above the hydraulic tightening vice 26 of the string of drill pipes. This guiding vice enables the diver in charge of the machine to rapidly and effectively supply the various successive pipes of the string of drill pipes.

Referring now to FIGS. 2 and 3, it can be seen how the bracket 20 hingedly mounted on a horizontal axis of two pins- 43 can be tilted by means of a hydraulic cylinder 44 through a given angle a with respect toa vertical line z'z. This angle a is automatically determined by the length of the piston stroke of the cylinder 44, the said length being advantageously adjustable. The angle a is selected so that when the bracket is in a tilted position, such as shown in FIG. 3 by dot-and-dash lines, the cable pulling pulley 45 of the winch 41 is exactly perpendicular to the drill hole. Thus, when a core barrel is to be withdrawn after a coring operation, it is sufficient to tilt the bracket 20 backwards, to let then the core extracter suspended to a cable by'means of a winch 41 and then to lift the core extracter and the core barrel by the same means. It should be noted that the winch 41 may also be used eventually for rapidly pulling out the string of drill pipes.

According to a modified embodiment of the invention, there may be provided a pivoting of the bracket 20 about the vertical with respect to the base 21, so that at a given angle the pushing screw 2lis placed opposite to the drill hole, whereas in at least one other angular position the pulley 45 of the winch 41 is vertical to the drill hole. In either cases, the various drilling and coring operations are simplified and ac celerated. j

FIG. 2 also shows in dot-and-dash lines (on the lefthand side of the FIG.) a lowermost position of a leg 22 when the machine is used, for instance, on a sharply sloped sea bed.

At 23 in the same FIG. is also represented a turntable connected to its guiding carriage in lowermost position on rails 35, as well as the uppermost position 23' of the turntable in dot-and-dash lines.

Reference is now made more particularly to FIGS. 4 and 5 illustrating more precisely the operation of the turntable 23 and the pushing assembly 24.

Referring first to 4, the operating principle is as follows. The hydraulic motor 36 drives a gear 37 which, in turn, rotates a gear forming a nut 48 screwed on the pushing screw 25. The latter is prevented from turning with respect to the frame (the bracket 20) by means of the slot 39 (FIG. 1) and a projection integral with the frame and sliding in the said slot. The rotary motion of the motor 36 compelling the nut 38 to rotate therefore results in a motion of translation of the pushing screw 25 upwards or downwards depending on the direction of rotation of the motor 36. Of course, thrust bearings 46, 47 (FIG. 5) are provided to prevent translation of the nut 38 while allowing it to rotate, the said thrust bearings 46, 47 being mounted in a housing 48 maintaining the pushing assembly in a suspended state. The housing 48 is hingedly mounted at 49 on the bracket 20. It is also integral with a toggle or knuckle 50 mounted in two dome-shaped bearings 51, 52 integral with the bracket. The pushing screw 25 moves freely through the toggle 50 and the bearings 51, 52.

The pushing action exerted by the pushing assembly 24 on the screw 25 tends to raise or lower the turntable 23, depending on the drive. The pushing action of the screw 25 is transmitted to the turntable through the medium of a toggle 53 mounted in two semispherical bearings 54, 55 secured to the housing 56 of the turntable. The turntable 23 moves in the vertical direction along the rails 35 and is guided by two carriages 34 each provided with, for instance, four lateral guiding rolls 57 and two longitudinal guiding rolls 58.

As already mentioned, the turntable comprises a hydraulic motor 32 driving a gear 59 which, in turn, rotates a gear 60 integral with the screwing sleeves 61 of the string of drill pipes. As seen in FIG. 5, the gear 60 is rotatably mountedin the housing 56 by means of two bearings 62, 62 allowing the pushing action to be transmitted.

The turntable and pushing assembly just described are characterized by the following novel features: the pushing assembly 24 and the turntable 23 are respectively driven by separate hydraulic motors 36, 32. This novel arrangement results in increased adaptability of the machine and improved drilling conditions, owing to the fact that it enables to vary at every moment the rotational speed of the string of drill pipes and the pushing pressure exerted on the string. in addition. it enables to use novel working methods. For

- slackened, the sleeve 61'canbe unscrewed from the string of instance, in carrying out penetration tests. it allows to obtain 5 separate and continuous readings of the point load and the force of penetration. thus considerably facilitating the operation of the machine: the two toggle mounting of the pushing screw 25 allows a certain disalignment and taking up of plays which favor the operation of the machine: the hinged mounting of the pushing assembly 24 on the bracket 20 cooperates with the two-toggle mounting of the pushing screw 25.

I Reference is now made more particularly to FIGS. 5, 6 and 7 to describe the driving head 33 of the string of drill pipes. The said head consists essentially of the gear 60 and a screwing sleeve 61. The outer threaded bearing surface of the screwing sleeve 61 is seen at 53. On this bearing surface are screwed the various drill pipes of the string. On the hub end of the gear 60 is screwed a piston 64 slidingly mounted in the inner cylindrical hollow 65 of the screwing sleeve 61. A crown 66 fixed by means of eight screws 67 to the lateral cylindrical wall of the sleeve 61 limits the stroke of the piston within the hollow 65.

The rotation of the sleeve 61 integrally with the hub 60 of the gear 60 is ensured by means of a key 68 fixed to the hub of the gear 60 by means of two screws 69.

The driving head of the string of drill pipes operates as follows.

During the drilling operation the gear 60 is-rotated by the gear 59 and the motor 32 and is translated by the pushing screw 25 acting upon the frame 56 and through the medium of the bearing 62. The hub of the gear 60 thus pushes the crown 66 and the latter covers the sleeve 61. in fact, a wearing ring (not shown for the sake of clarity) is provided to transmit the pushing action onto the sleeve and also to ensure a sealing between the stationary housing 56 and the rotating hub of the gear 60. In this drilling position, the piston 64 secured to the hub 60' is substantially at the bottom of the hollow 65, as shown in FIG. 5. The rotation is imparted to'the handle 61 by the key 68 as described above.

When it is desired to unscrew the handle from the string of drill pipes, for instance in order to couple an extension, the pushing pressure of the screw 25 is slackened by slightly raising the screw. As a result, the piston 64 rises in the hollow 65. The pushing position is diagrammatically shown in FIG. 10 at a larger scale, whereas the pulling position is illustrated in F IG. 7. In these FIGS. the piston 64 and the hub 60' of the gear 60 are shown as forming one piece with one another, and

also the crown 66 and the sleeve 61'. The mutual functions of drill pipes (not shown) by reyersing the direction of rotation of the motor 32.

Advantageously this reversal of rotation is allowed only in case the hydraulic vice 26 (FIG 1) for tightening the string of drill pipes has initially been tightened. To this end. a hydraulic safety coupling device is provided between the reversal drive of the motor 32 and the tightening drive of the vice 26.

Once the vice 26 has been tightened, the motor 32 is reversed and the sleeve is unscrewed on the string of drill pipes. The sleeve thus rises, but this motion is permitted by the sliding of the sleeve 61 on the piston 64 even though the pushing screw 25 is not simultaneously driven upwards. Thus, the thread on the string of drill pipes is prevented from being injured as was frequently the case in conventional devices where it was necessary to synchronize the upward motion of the pushing screw with the unscrewing of the string of drill pipes, in spite, of the different thread pitches of the pushing screw and the string of drill pipes.

in this connection it should be noted that the drilling mud conveyed under pressure into the string of drill pipes by the hollow pushing screw 25 and acting, in particular, in the hollow 65 between the piston 64 and the sleeve 61 form hydraulic damping means additionally favoring the unscrewing of the strings of drill pipes.

H65. 8 and 9 illustrate a convenient embodiment of the hydraulic vice 26. it is seen that this vice makes use of two jaws 70, 71 actuated by two hydraulic cylinders 72, 73. One advantage of this device consists in that it is easy to use and drive and, in particular, in that it facilitates automation.

As already mentioned, all the working pieces of the machine are advantageously immersed in oil or in any other suitable hydraulic fluid and are enclosed in impervious box girders. The work of the seals is reduced to a minimum by using an internal hydraulic pressure substantially equivalent to or, preferably, slightly above the external hydrostatic pressure. For instance, this balancing of the pressures can be obtained automatically by placing the hydraulic fluid container aboard the ship on which the power generator is mounted. An automatic balancing of the pressures is thus obtained as a result of the higher level of the ship with respect to the water and the substantially equivalent densities of the water and the hydraulic fluid being used. A slight overpressure in the hydraulic system may eventually be provided, in particular when the machine is eventually stopped. For instance, one can manage to obtain at all points a slight overpressure of approximately 0 .5 bar of the hydraulic fluid over the surrounding water medium.

Of course, the machine according to the invention may be used with or without notable modifications to perform land drillings. it is 6 be understood that the invention should not at all be construed as being limited to the form of embodiment shown and described herein which has been given by way of example only. In particular, the invention comprises all the means constituting technical equivalents to the means described as well as their combinations, should they be carried out according to the spirit, principles and teachings of the invention as defined in the appended claims.

lclaim:

1. A drilling machine for underwater drillings comprising a driving head for the machine, a base, an upwardly directed bracket mounted on said base, adjustable legs for said base for resting on the ground, guideways in the bracket, a carriage movable upwards and downwards along said guideways, means mounted on said carriage for rotating the driving head of the machine, a toggle joint, a pushing screw the lower end of which bears against said carriage through said toggle joint, a nut screwed on said screw, driving means for rotating said nut, a housing connected to said bracket and hingedly mounted around an axis which is orthogonal to the direction of the pushing screw, said driving means being mounted in said housing, and means for supplying pressurized powering hydraulic fluid for rotating said driving head and said driving means of the machine.

2. A drilling machine according to claim 1, wherein the means which drive said nut and which rotate said driving head include variable-speed motors, the rotational speed of which ranges from a few fractions of a revolution per minute to several hundreds or thousands of revolutions per minute.

3. A drillingmachine according to claim 1 wherein said bracket is hingedly mounted atits lower end around an axis which is orthogonal to said pushing screw, an hydraulic cylinder is provided having one of its ends articulated to said base and its other end articulated to said bracket, a winch is provided at the upper end of said bracket, the stroke of said hydraulic cylinder being such that when fully extended said bracket is orthogonal to the plane of the base and when fully retracted said winch is in the vertical axis of the drilling hole.

4. A drilling machine according to claim 1 wherein said housing is connected to a toggle which is mounted in two semispherical bearings secured to the upper end of said bracket, an axial here being provided insaid toggle and in said bearings and through which said pushing screw passes.

5. A drilling machine according to claim -I wherein said driving head comprises a handle provided at its lower end with a threaded portion on which is screwed a string of drill pipes, a gear rotated by said rotating means and. having a hub, the lower face of which bears against the upper face of said handle, key means locking said nutiand said handle together in rotation, piston means solid with said hub and freely mounted in axial translation in a central cylindrical bore provided in said handle and means provided at the upper end of said handle limiting the upward movement of said piston means in said cylindrical bore. 

